1. Field of the Invention
The present invention relates to a pipe rehabilitation method for rehabilitating an existing pipe in which integrally formed plastic segments each comprising an inner surface plate constituting an inner circumferential surface, and side plates and end plates provided upright on peripheral edges of the inner surface plate are linked in the circumferential direction and in the pipe-length direction.
2. Description of the Related Art
In cases in which a sewage pipe or another pipeline buried underground has deteriorated through aging, a pipe lining method has been proposed and practiced in which a lining is provided to the inner circumferential surface thereof to repair the pipeline without excavating it from the ground.
In this pipe lining method, a pipe lining material made of a tubular resin absorbent material impregnated with an uncured thermosetting resin is everted and inserted into a pipeline using fluid pressure, and is pressed by fluid pressure against the inner peripheral wall of the pipeline. The lining material is then heated using a desired method to cure the thermosetting resin impregnated therein and form a plastic pipe, thereby repairing the pipeline.
There is also known a lining method using segments each comprising an inner surface plate constituting an inner circumferential surface, side plates and end plates provided upright on the peripheral edges of the inner surface plate, these plates being integrally formed from a plastic material.
The segments are linked in the circumferential direction to assemble short pipe units, which are then linked in the pipe-length direction to construct a rehabilitation pipe inside an existing pipe (for example, JP-A 2011-12803). Such a pipe rehabilitation method is used for large-diameter existing pipes. In this method, after assembling a rehabilitation pipe inside the existing pipe, grout or another filler material is injected into a space between the existing pipe and the rehabilitation pipe and hardened to construct a composite pipe.
When a rehabilitation pipe is to be installed in a construction site, there may be instances in which the diameter of the rehabilitation pipe must be made slightly larger than the standard size in order to compensate errors that have arose in constructing the existing pipe or to match other structures. To this end, a diameter expander is inserted between the segments when they are linked in the circumferential direction to enlarge the diameter of the rehabilitation pipe (JP-A 2014-77261).